, Volume 23, Issue 6, pp 1670-1679

Measurements of the characteristics of spray droplets using in-line digital particle holography

Abstract

In-line digital particle holography is applied to measure the characteristics of spray droplets. Common reconstruction methods were considered and the best one was selected. Several important parameters at the time of hologram recording, such as the object distance and the region of laser beam used, are discussed. The feasibility of the correlation coefficient (CC) method for focal plane determination of 3-D droplets was verified. A double exposure hologram recording system with synchronization system for time control was established, and two digital spray holograms were obtained in a short time interval. For post-processing of reconstruction images, the two-threshold and the image segmentation methods were used in binary image transformation. Using the CC method and some image processing techniques applied to droplets in each double exposure image, the spatial positions of droplets used to evaluate the three dimensional droplet velocities were easily located, which proved the feasibility of in-line digital particle holographic technology as a good measurement tool for spray droplets.

This paper was recommended for publication in revised form by Associate Editor Gihun Son
Boseon Kang received his B.S. and M.S. degrees in Mechanical Engineering from Seoul National University in 1986 and 1988, respectively. He then went on to receive his Ph.D. degree from University of Illinois, Chicago in 1995. He is currently Professor at School of Mechanical Systems Engineering, Chonnam National University in Gwangju, Korea. His research interests are in the area of sprays, holographic techniques in thermofluid measurements.
Yan Yang received his B.S. degree in Mechanical Engineering from Chongqing Insitute of Technology in 1997, and received his M.S. degree in Mechanics from Chongqing University in 2005. He is doctoral student of Department of Mechanical Systems Engineering, Chonnam National University in Gwangju, Korea. He is also currently Associate Professor at Automobile College, Chongqing University of Technology in Chongqing, China. His research direction is digital holographic techniques